The technique of embolization involves the introduction of particles into the circulation to occlude blood vessels, for example, so as to either arrest or prevent hemorrhage, or to cut off blood flow to a tissue or an organ. Blood vessel occlusion is desirable for managing various diseases and conditions. An embolization procedure is typically associated with an insertion of a catheter or a microcathter (depending on the size of the target blood vessel) into a blood vessel and injection of an embolic agent through the catheter/microcatheter. The embolic agent is chosen, for example, based on the size of the vessel to be occluded, the desired duration of occlusion, or/and the type of disease or condition to be treated (e.g., hypervascular tumors, uterine fibroids, etc.), among other factors. Widely known embolic agents are oils, foam, plug, microspheres. or beads.
A follow-up angiogram may be performed to determine the specificity and completeness of an arterial occlusion. Blocking the blood supply to the tissue is intended to result in shrinkage or/and death of the tissue.
Embolization therapy is currently used to treat advanced liver cancer in patients that are not candidates for liver transplantation or liver resection. and also employed for treating other cancer types. There are currently numerous embolic therapies available. Exemplary therapies are trans-arterial embolization (or TAE), transarterial chemoembolization (TACE), drug eluting bead (DEB) therapy, and trans-arterial radioembolization (TARE).
TAE (also known as bland embolization) utilizes embolic particles injected into arteries feeding the tumor to stop blood flow to the tumor, thus causing necrosis. Typically, the embolic particles do not contain a drug.
TACE involves initial localized injections of a chemotherapeutic drug followed immediately by injection of embolic particles to prevent drug reflux and to cause embolization. TACE provides for both embolization (necrosis) of tumor cells and chemotherapy.
DEB involves combining/integrating an (elutable) drug into embolic particles, and similar to TACE involves two modes of action. In contrast to TACE, DEB provides sustained drug release. However, currently available DEB products show in-vitro rapid release (i.e., within hours) of the drug from the embolic particles. Also, current DEB therapy utilizes biostable particles, thereby precluding re-treatment. Embolic therapies are not curative, however, in most therapeutic situations, a single therapy delays tumor progression.
Trans-arterial radioembolization (TARE) involves (injective) administration of radioactively labeled microspheres into a blood vessel. The injected microspheres emit radiation to surrounding tissues which then undergo necrosis.
In spite of known teachings and practices in the field and art of the invention, there is an on-going need for developing new and improved injectable embolization particulates (e.g., particles, microstructures, beads), compositions thereof, and methods for using such in embolization procedures.